period two
Sound Perception and
Rating Methods
notes
Phon and Sone |
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| 120 |
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| loudness level (phons) |
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| 120 |
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Pam |
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100 |
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| 110 |
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20 |
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| 100 |
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| 90 |
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ref | 80 |
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| 80 |
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dB |
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| 70 |
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pressure, | 60 |
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| 60 |
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| 40 |
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| 50 |
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sound |
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| 40 |
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20 |
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| 30 |
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| 20 |
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| 0 |
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| 10 |
| 10,000 |
| 20 | 50 | 100 | 200 | 500 | 1,000 2,000 | 5,000 | |
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| frequency, Hz |
| Figure 31 |
The phon is another descriptor used to indicate loudness with a single number. The loudness of a sound, expressed in phons, is equal to the sound- pressure level of a standard sound, at 1,000 Hz, that is considered equally loud. For example, a sound pressure level of 40 dB at 1,000 Hz is considered to have a loudness of 40 phons. Any sound that falls on this same loudness curve, at any frequency, would also be described as having a loudness equal to 40 phons.
While the phon scale is logarithmic, the sone is the linear equivalent to the phon. In principle, the sone scale is linear when compared to the response of the human ear. For example, two sones is twice as loud as one sone, and half as loud as four sones.
While the phon and sone scales are not widely used, some HVAC equipment, primarily
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